Heart failure is a condition effecting millions of people worldwide. Heart failure includes failure of either the left side of the heart, the right side of the heart, or both. Right heart failure can lead to elevated right atrial pressures, and the elevated right atrial pressures in turn can lead to serious clinical conditions, including impaired renal function. More specifically, right heart failure can lead to elevated renal vein pressures, which in turn may cause additional adverse conditions in the body. There exists a need to percutaneously treat the symptoms of right heart failure by preventing the elevated pressure from harming key vessels and organs in the body.
A few techniques have been disclosed as a means of treating right heart failure. U.S. Pat. No. 7,159,593 issued to Quijano et al. discloses a pair of stented valves. One valve sits at the right atrium (RA)/Inferior Vena Cava (IVC) junction, while the second stented valve is implanted at the RA/Superior Vena Cava (SVC) junction. Such an approach suffers from deficiencies. The foremost problem with such approach is that no consideration is given to the effect that implanting a valve in both the SVC and IVC would have on the blood pressure in RA and coronary sinus. With both the upper and lower body blocked off by stented valves, the blood pressure in the RA would climb dramatically, causing the RA to balloon to a hazardous size. The second major problem with the approach disclosed in Quijano et al. is the anatomical difficulties related to implanting a stented valve at the junction of the IVC and the RA. The RA/IVC junction is often flared (the IVC diameter increases from lower to upper part) and has an asymmetrical conical shape which does not lend itself well to a tubular implant. Additionally, the anatomical differences from person to person in this area would make designing a stented valve for a large population impractical. For example, the angle of the IVC to the RA can vary dramatically from person to person, and may also change as heart disease progresses. Still further, there may or may not be a Eustachian valve at the RA/IVC junction, depending on the individual anatomy. This valve could interfere with device deployment, safety and/or function. Finally, Quijano et al. do not address the problem of accidental hepatic vein occlusion by the device in question. The hepatic veins reside just below the RA/IVC junction, and their location is highly variable. Occasionally the hepatic veins empty out into the IVC in the immediate vicinity of the junction with the RA. Based on these errors and omissions, it seems clear that there still exists a need for a reliable means of treating right heart failure and elevated venous pressures.
U.S. Pat. No. 7,350,995 to Quijano et al. discloses a pair of stented tissue valves which are connected by means of various connecting members. This disclosure suffers from all of the above-mentioned deficiencies, and does not address any of the above physiological problems associated with implanting valves in both the SVC and the IVC. Therefore there still exists a need for a reliable means of treating right heart failure and elevated venous pressures.
U.S. patent application Publ. No. 2005/0049692 by Numamoto et al. discloses the use of a stented valve to treat right heart failure. The valve may be placed in the SVC or the IVC. The inventors teach that the IVC valve should be placed in the vicinity of the junction between the IVC and the RA. They also teach that the device should be placed above the hepatic veins. This disclosure fails to address the problems associated with varying anatomies and the difficult geometry of the RA/IVC junction. The disclosure also does not address the problem of accidental occlusion of the hepatic veins. Additionally, the inventors do not disclose a means of preventing excessive blood pressures from building up in the upper body. Therefore, there still exists a need for a reliable means of treating right heart failure by safely controlling elevated venous pressures.